The most common side effect of the nicotine patch is a rash on the skin where the patch is worn. Moving the patch to a new area of skin each day will help reduce skin irritation, and there are also medicated skin creams available at pharmacies.
Some people have sleep disturbances or vivid dreams (more likely with the high dose 24 hour patch). In these cases, it's recommended that you either take off the 24 hour patch just before bedtime, or switch to the 16 hour patch.
Less common side effects include headache, nausea and indigestion. Most users rate these reactions as mild. If side effects do not fade within a week or two, or they worry you, see your pharmacist or doctor.
Serious side effects are uncommon, and are described in the Consumer Medicine Information (pack insert) that comes with the patches. If you have these symptoms, follow the instructions in the leaflet and see a doctor as soon as possible. Do not smoke.
Using the patch is always safer than continuing to smoke. Tobacco smoke contains many cancer-causing substances, carbon monoxide and other dangerous chemicals, which the nicotine patch does not. Unlike smoking, nicotine is not a major cause of increased risk for cancer or heart disease. The patch does not increase the risk of heart attack in smokers who have stable heart disease.
It is important to store and dispose of patches so that children and animals cannot get them, as they can be dangerous for them.